The latest Release Candidates in the PHP 5.3.x and 5.4.x series and are available for download and testing - PHP 5.3.18RC1 and PHP 5.4.8RC1:

We've released PHP 5.3.18RC1 and 5.4.8RC1. This is a regular bugfix release, the full list of issues fixed can be found in the NEWS files. Please test and report if anything is broken. If no critical issues is found in this RC, the final version will be released in two weeks.

Bugs fixed in this release include issues with is_callable, the catching of an exception in an __autoload call, fixes for the SOAP an dSPL extensions as well as updates to the CLI server (501 response, PATCH support) and changes to the DOM, FPM and cURL extensions. You can download these latest Candidates and get testing here: